17. OpenCV - City Tech OpenLab

1/10/2015
FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
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find­object
Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIEF
and other feature detectors and descriptors.
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FindObjectsWithWebcam Find objects with a webcam
Updated Jun 5, 2014 by matla...@gmail.com
Introduction
Details
TCP information
Introduction
This tutorial will show how to add an object using your webcam. Note that version 0.4 is used here. Details
1. Open Find­Object application.
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
2. If it is the first use of Find­Object, go to next step; otherwise, restore all default settings (menu "Edit­>Restore all default settings")
3. Press space to start the webcam. Note that by default, the view is mirrored (you can change this with a right­click on the scene or by
changing the parameter "General/mirrorView" using menu "View­>parameters").
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
4. Open "Edit" menu and select "Add object from scene...".
5. Place an object in front of the camera and press "Take picture".
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
6. Select the region representing the object.
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
7. Press next to verify your selection. Then press "End".
8. Back to main window, you should see the object in the side pane.
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
9. Put your object back in front of the camera to see the detection.
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
If the scene doesn't have many features, there may have some bad detections like below. If your scene doesn't contain many features,
try General/InvertedSearch mode. For the next, this mode is used.
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
10. You can add more objects if you want.
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
11. You can also right­click on the camera view and uncheck "Show features".
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
TCP information
Find­Object 0.4.3 required
Some information about objects detected like ID and position are sent over TCP on a port.
Publish detected objects (with position, rotation, scale and shear), formatted as [ObjectId1, objectWidth, objectHeight, h11, h12,
h13, h21, h22, h23, h31, h32, h33, ObjectId2...] where h## is a 3x3 homography matrix (h31 = dx and h32 = dy, see QTransform).
Example handling the message (TcpClient.cpp, TcpClient.h and main.cpp).
Raw format: [quint16 (size in bytes of the following QVector<float>) QVector<float>]. The QVector<float> should have a size of 12 float *
number of objects.
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
Note that parameter Homography/homographyComputed must be true (default true) in order to publish the topic.
Parameter General/mirrorView would be false in order to visualize correctly the homography values returned.
You can set manually a port, see parameter General/port.
On ROS, a topic named "/objects" containing the same data is sent. See here.
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
Comment by mikezmab...@gmail.com, Oct 5, 2013
can it be applied to opencv using c#?
if so, please do send me tips and steps.
also, can you gave me codes for it..
Comment by AfnanAli...@gmail.com, Jan 26, 2014
hey just a question but how can we access the code so that we may add more of the yellow dots that recognize features?
Comment by kuh...@bluemail.ch, May 5, 2014
Hi! Wow, that's exactly what I need! How do I access the information (picture­number and ­position)? Does the program give out the information on a
port? Greetings
Comment by project member matla...@gmail.com, May 5, 2014
Sorry for previous comments, I didn't receive notifications when comments were posted, I just added a new rule in my google code settings. So here
the answers:
@mikezmabulay If the .NET wrappers of OpenCV (like http://sourceforge.net/projects/opencvnet/ or http://www.emgu.com/wiki/index.php/Tutorial)
expose the same methods that are used in the code here, it may be work in C#. For all GUI interface, Qt is used here.
@AfnanAli847? The number of yellow dots depends on how many features are extracted (from the chosen keypoint detector). In the code,
ObjWidget?::setKptColor(int index, const QColor & color) is used to set the color of specified features.
@kuhn.f@bluemail.ch For now, only the ROS version of the code provides this output (objects detected with position). See
https://code.google.com/p/find­object/#ROS. Though since many persons are using the code on Windows/Mac OS X/ Ubuntu without ROS, I added a
new issue to add this feature (https://code.google.com/p/find­object/issues/detail?id=19).
Comment by ii...@yahoo.com, May 13, 2014
thats not at all the given object you are recognizing garbage
Comment by project member matla...@gmail.com, May 14, 2014
https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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FindObjectsWithWebcam ­ find­object ­ Find objects with a webcam ­ Simple Qt interface to try OpenCV implementations of SIFT, SURF, FAST, BRIE…
If you have problems with false detections, try to increase the parameter Homography/minimumInliers to 20 or more. You can set also
Homography/ignoreWhenAllInliers=true.
Comment by Ryan.K.C...@gmail.com, Dec 8, 2014
I'm using somrthing like this for a science experiment at school and need some help. I've got it all working but I'm not very good at codeing :/ Is
there a way that some codeing can be incorporated that would force the webcam to take a picture of an object when that specific object is placed in
front of the camera? I've been working on this for a little over a month now, and any help would be appreciated!
Comment by project member matla...@gmail.com, Dec 9, 2014
It is possible. In the code, you could add this code in the if(info.objDetected_.size() > 0) at this line:
if(info.objDetected_.size() > 0 || Settings::getGeneral_sendNoObjDetectedEvents())
{
Q_EMIT objectsFound(info);
+
+
QString path("screenshot.png");
+
ui_->imageView_source->getSceneAsPixmap().save(path);
+
UINFO("Saved %s!", path.toStdString().c_str());
}
If you don't want to edit the code, you may use the TCP detection above to know when to trigger a screenshot on the camera (See "Example
handling" above to know how to do a TCP client). An example would be to use in the TCP client a cv::VideoCapture? of OpenCV and to use
cv::imwrite() to save the image when the TCP msg is received.
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https://code.google.com/p/find­object/wiki/FindObjectsWithWebcam
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